Xcode "Size to fit contents" disabled

ios, resize, xcode

Solution

I fixed the issue by dragging around the labels and resizing them (randomly) manually and then the option was enabled!

Problem

I am following the Stanford lectures on developing apps for iOS and I've run into a bit of a problem. The lecturer says to click on a label from the Document Outline and then go to Editor > Size to fit contents in order to remove the fixed size constraints. However my problem is that "Size to fit contents" is disabled and I cannot click it (see image). Any idea what I'm doing wrong?

Original source